The proposal is to continue a training program in cancer research at Columbia University that was established in 1984. The rationale of the Cancer Biology Training Program is to identify and recruit individuals with outstanding potential and prepare them for highly productive careers in cancer research. This will be achieved by offering a rigorous didactic curriculum, providing opportunities for cancer research in the laboratories of Columbia University faculty, and fostering an interactive environment in which trainees can gain exposure to the full range of scientific disciples involved in cancer research. Funds are initially requested to support 6 postdoctoral and 4 predoctoral trainees. The participating faculty are selected on the basis of the cancer focus and quality of their research programs, their record of productive interactions with other cancer investigators, and their experience in training postdoctoral fellows and predoctoral students. Trainees are chosen competitively according to the cancer focus and quality of their proposed research project, their past academic and research performance, their future potential as independent investigators, and their commitment to a career in cancer research. The Cancer Biology Training Program will benefit greatly from a dramatic expansion of cancer research that is now underway at Columbia University. This expansion is driven by the opening in 2005 of the Irving Cancer Research Facility, a new 300,000 square-foot 10-story building devoted entirely to cancer research. To occupy this facility, Columbia University and New York Presbyterian Hospital have made large investments to recruit leading scientists in the basic, translational, and clinical arenas of cancer research. Most of these recruits should become active participants in the Cancer Biology Training Program by 2007. These developments should broaden the scope and enhance the quality of the Cancer Biology Training Program, as well as attract a superior pool of trainees seeking academic careers in cancer research.